The rationale of this study is to combine two distinct kinase inhibitors to evaluate synergistic inhibition of angiogenesis and epidermal growth factor receptor (EGFR) signaling. Erlotinib is a oral tyrosine kinase inhibitor that targets EGFR. Sorafenib is a oral tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR), platelet derived growth factor receptor beta, Raf-1, Flt-3, and C-kit. These agents also do not exhibit overlapping adverse event profiles which provided additional support for studying this combination therapy.